Murfreesboro is a city in Pike County, Arkansas, United States. The population was 1,764 at the 2000 census. The city is the county seat of Pike County. Crater of Diamonds State Park is located just to the south. The crater is an eroded lamproite pipe where diamonds were discovered in 1906. 100,000 were found by 1933, and visitors to the park may still take away whatever they can find.
The guard cells surround each stoma in a plant cell. They regulate  the opening and closing of stomata to facilitate gas exchange and  control transpiration in plants.
Guard Cells Function. Photosynthesis 1When the guard cells lose water on a hot day, they become deflated and push together, thus closing off the stoma. This cleaver strategy prevents the plants from dehydrating. Stomata open when K+ enters guard cell followed by water; stomata close when ... How do stomata open? Stomata sense environmental cues, like light, to open. ... croptechnology.unl.edu/viewLesson.cgi?... Guard cells open because of the osmotic entry of entry. Asking about Life - Google Books Resultby TOBIN, Allan J. Tobin, Jennie Dusheck - 2004 - Science - 1 pages Abscisic acid inhibits the flow of potassium ions into the guard cells, the cells lose water, and the stomata close.